Production of benzanthrone derivatives



Patented June 8, 1926,

UNITED STATES) PATENT OFFICE.

GEORG' KALISCHEB, OI MAINKUR, NEAR FRANKFORT-ON-THE-MAIN, AND RUDOLFMfi'LLER AND FRITZ FBISTER, OF FECHENHEIH, NEAR FRANKFOB'I-ON-THE-MAIN,

GERMANY.

PRODUCTION OF BENZANTHRONE DERIVATIVES.

No Drawing.

Original application filed March 19, 1925, Serial No. 16795, and inGermany December 24.

1924. Divided and this application filed August 17, 1925. Serial No."50,844.

Ve have found that benzanthrone der1va-, tives may be obtained accordingto a new process entirely different from any one used hitherto and whichconsists in reducing or- 5 naphthalene-azo-benzene-m-carboxylic acid orthe substitution products thereof to the hydrazocompounds, intransforming the lit-naphthalene-hydrazo-benzene-m-carboxylric acidsthus obtained in acid solution into the4.4-diaminonaphthylphenyl-2'-carboxylic acids in replacing by means ofthe socalled Sandmeyer method the two aminon it iin Thea-naphthalene-azo-m-carboxylic acid or its substitution products servingas starting materials for the new process may be obtained by boilingwith alcohol the drawcompounds of the azo dyes, Which are formed bycombining diazobenzene-m-carboxvlic acid with a-naphthylamine or itsderivatives. Generally speaking only those derivatives ofa-naphthalene-azo-benzene-mcarboxylic acid can be used for the newprocess, in which the ana-5- os1t1on corresponding to the azo group 0the naphthalene nucleus and the two positions to the no group (theC-atoms mar ed in the first formula y a are not substltuted.

The reduction of the azocompounds may be efiected with all the reducingagents used groups of the 4.4-diaminonaphthylphenyl- 2'carboxylic acidsthus obtained by hydrogen, halogen, hydroxyl, methoxyl etc. and incondensing the products thus obtained into derivatives of benzanthrone,hologenbenzanthrone, hydroxybenzanthrone, etc. 1

The different phases of the reaction may be represented by the followingformulae, dichlorobenzanthrone used as prototype for the whole class ofbenzanthrone. derivatives obtainable by the new process CODE 00011 meansof the various forms of the so-called Sandmeyer reaction. In thisimannere. g. by treating with hydrohalogenic acids in the resence of copper orcuprous salts, halogen erivatives, by treating with diluted. sulfuricacid hydroxyl derivatives are obtained,

whilst by treating e. g. with alcohol the ex change of the diazogroupsinto hydrogen is effected.

The naphthylphenyl-Q-carboxylic acids or their substitution products canbest be conconverting the acids at first into the chlorides and bytreating the latter with aluminiuin chloride.

The ben'zanthrone derivatives thus ob tained are valuable intermediateproducts for the production of vat dyestuffs of the violanthnone andisoviolanthrone' series.

In order to illustrate our present invention we give thefollowing'examplez Emampl e.

A suspension of 48 kg. of the sodium salt of thea-naphthaleneazobenzene-mcarboxylic acid, obtainable by boiling thediazocompound of the (lyestuff from m diazobenzoic acid anda-naphthylamine with alcohol, in 200 kg. alcohol is allowed to runwithin hour at 50 into a solution of 112 kg. stannous chloride in 360kg. concentrated hydrochloric acid, the temperature being kept below Inorder to ensure complete transformation, the solution is stirred forsome time at 50 and the reaction product is then separated byfiltration. For purifying the dihydrochloride of the4:.4'diaminonaphthyIphenyI-Q-carboxylic acid thus obtained, the rawproduct is dissolved in hot water and separated again as a light greysediment by the addition of concentrated hydrochloric acid. By addition,of

the calculated amount of al li, the free diami no naphthylphenylcarboxylic acid, which is sparingly soluble in water, is precipitated,whereas with an excess of alkali the easily soluble sodium salt isformed. By the action of nitrous acid an easily soluble golden yellowtetrazocompound is obtained, which yields with R-salt a violet dyestuff.

17 kg. of the 4.4'-diamino-naphthylphenyl- 2-carboxylic acid aretetrazotized in a hydrochloric acid solution in the customary manner;the tetrazo solution is run at into a solution of cuprous chlorideprepared from 27 kg.,cop er sulfate. The reaction is completed by eatinfor, some time to 8090, and the 4.4-d1chloronapthylphenyl- 2-carboxylicacid, which separates as a red powder is filtered off. For the purposeof .dilute caustic soda solution and again precipitated with acid. Thetransformation into the dichlorobenzanthrone takes place for instance bydissolving in 10 times its weight of chlorosulfonic acid at atemperature not exceeding 10 and by allowing the reaction mixture toflow on an excess of ice. The dichlorobenzanthrone is obtained in theform of brown-yellow crystals, which melt at about 215 whenrecrystallized from glacial acetic acid. The solution in concentratedsulfuric acid is reddishvbrown colored with a red fluorescence. In asimilar manner the dichloro products of substituted benzanthrones may beproduced by starting fromthe corres ondingdiamino-naphthylphenyl-carboxylic acid.

The exchange of the diazo group for other groups such as hydrogen,hydroxyl, etc. may likewise easily be efl'ected according to the usualmethods. For instance, the 4.4'-diamino 7methoxynaphylphenyl-2-carboxylic acid is converted into the7-methoxynaphthylphenyl-2'-carboxylio acidby boiling the tetrazocompound with alcohol. This compound, which is obtained in form of abrown powder, is then transformed into the corresponding4-methoxybenzanthrone by treatment with acid condensing agents asindicated above.

The Bz-2-methox benzanthrone is likewise obtained by sub ecting the4.4-diamino- 3-methoxynaphthylphenyl-2-carboxylic acid to the sameprocess.

Having now particularly described and ascertained the nature of oursaidinvention and in what manner the same is to be performed, We declare,that what we claim is:

1. Process for the production of benzanthrone derivatives which consistsin treating a-naphthalene-azo-benzene-m-carboxylic acid (in which theC-atoms 4, 5, and 4 corresponding to the following formula:

- COOH com iounds thus obtained and represented by t e following generalformula:

means halogen, H, OH, OCH,, 00 11,. The C-atoms 2, 3, 5, 6, 7, 3, 5', 6'may be substituted by univale'nt groups (as CH halogens, O-alkyl), withacid condensing agents substantially as described. I

2. Process for the production of dichlorothe diazogroups by chlorine bymeans of the so-called Sandmeyer method and in condensing thedichloronaphthylphenyl-o-carboxylic acid of the following formula:

with acid condensing agents substantially as described.

In witness whereof we have hereunto signed our names this fourth day ofAugust GEORG KALISOHE-R. RUD. MU LER. FRITZ FRISTER.

